chechnya were raised in the u.s. but in recent years the olderbrother,tamerlan's, islamicfaith had become stricter. he'd stopped smoking and drinking and given up boxing. his uncle said he noticed those changes several years ago and spoke to a family friend. >> last time i spoke with tamerlan, 2009, and i was shocked when i heard his words. his phrases. it wasn't devotion. it was something as it's called been radicalized. he said there is someone who brainwashed him, some newly convert to islam. >> 2011 the russian government did ask the fbi to investigate tamerlan. the fbi says it checked data bases, interviewed tamerlan and family members but, quote, did not find any terrorism activity, domestic or foreign. on sunday some lawmakers said the fbi may have dropped the ball. >> anwr alaki. now this case with the older brother. this is at least the fifth case i'm aware of where the fbi has failed to stop someone who ultimately became a terrorist murderer. >> then in 2012 camm etamerlan traveled to dagestan where his mother was from and both parents live now. he stayed there for six mo

loose. dzhokhar tsarnaev. we know the olderbrothertamerlantsarnaevis dead. we know two people in custody, not necessary related, that live in the apartment that these two brothers live in. willie, you have been covering things overnight. give us the tick talk through that convenience store robbery to where we are right now. >> as pete williams is pointing out for us this morning this came out because of the actions of these two alleged terrorists. they decided to rob a 7-eleven at 10:20 in cambridge. they went and murdered a police officer sitting in his vehicle at m.i.t. that led to a carjacking. they took a black mercedes suv. they held at gunpoint the driver of that car for 30 minutes before releasing the driver unharmed. at that point, there's a chase and authorities come into the town of watertown, as mike barnicle described it for us this morning. a bedroom community of 32,000 people and there was a shootout in the streets of watertown. suspect number one. the one we have come to known in the black hat. was on the ground. authorities found him with an ied. improvised exp

roots in the chechnya region of russia. olderbrothertamerlanvisiteddagestan in 2012 a region in southern russia where his father and mother still live. in an interview with "the wall street journal" their mother said tamerlan had given your boxing and drinking and smoking as he turned to a religious life and told the paper he phoned her the night he died saying, quote, the police, they have started shooting at us. they are chasing us. telling her he loved her before the phone went silent. and his uncle who lives in maryland says he believes the older brother became radicalized in cambridge and not overseas and eventually drew in his younger brother but lawmakers say more questions about their past need to be answered. >> we believe they may have traveled on an alias to get back to his home country and that seven months, six and a half months or so becomes extremely important. so you know he had some radicalization before he left, you know he probably didn't travel on his own name or some variation of his own name, and when he comes back, he has a renewed interest in that radi

off, a surveillance camera shows dzhokharandtamerlantsarnaevwalking toward the boston marathon finish line with backpacks. then a surveillance camera mounted on the restaurant nearby captures crucial pieces of evidence. seven minutes before the first bombing the video which still hasn't been released shows dzhokhar walking toward the second bombing site. three minutes later he works his way into the crowd and takes his backpack off. the fbi says still photos show the backpack on the ground at his feet. when the first bomb goes off, tsarnaev remains calm as the people around him respond to the blast. he walks away without his backpack and ten second later the second bomb goes off in the spot where he left the backpack. complaint reveals that agents searched dzhokhar tsarnaev's u. mass dartmouth dorm room and they found bbs and large pyro tech. investigators found a bomb of the same brand of pressure cooker used in the bombs in the thursday night shoot-out. >> within minutes i had six of my officers, four on duty, two off duty, that are engaged in this gun fight. it continues and

to the one in the surveillance photos he was allegedly wearing. investigators also want toquestiontamerlantsarnaev'swife. the couple initially met at a nightclub. she later converted to islam, dropped out of college and had a child with him. her attorney has said that she had no suspicions that her husband might be plotting an attack. hundreds of people stood in silence at copley square at 2:50 p.m. one week after the bombings. president obama marked the moment of silence from the white house. the u.s. senate held a similar tribute on capitol hill. >>> it is still unclear what impact the boston bombings will have on the immigration debate in congress but the topic of national security is clearly playing a more rom neprominent n the discussion. things got tense on capitol hill yesterday when senator chuck schumer sparred with republican senator chuck grassley about the future of the legislation. take a look. >> a few ways to improve the bill, offer an amendment when we start mark-up in may and let's vote on it. i say that particularly to those who are pointing to what happened, the terrib